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The Course of Martin Heidegger’s Notion of Science in His Early Thought,Based on Works Preceding Being and Time
, M.Sc. Thesis Sharif University of Technology ; Sefidkhosh, Meysam (Supervisor)
Abstract
In this research, first of all, the main question of Heidegger and his epoch is investigated. If we read Heidegger along the tradition of German philosophy, then it is perceived that the problem of science is the most central subject matter standing against Heidegger. My question is this: how Heidegger reaches to this existential phenomenological view about science. Regarding that, by giving a coherent narration about a crucial problem called 'the crisis of science', in the first chapter I gave a short view to philosophies preceding Heidegger, some important of which is Dilthey's philosophy of life, phenomenology of Husserl, and south-west school of neo-Kantianism. The second chapter...
Numerical Simulation of Liquid Jet and Bubble Collapse Interaction near the Wall
,
M.Sc. Thesis
Sharif University of Technology
;
Javadi, Khodayar
(Supervisor)
Abstract
Bubble collapse near a rigid wall with rapid and non-spherical compression of the internal gas can lead to destructive and unfavorable effects such as erosion, noise, and a fall-off in the performance of devices. Despite the fact that several investigations on this phenomena have been carried out under various conditions, studies indicate that the collapse of a single cavitation bubble next to the liquid jet injected from the wall's side and their interaction have not been studied so far. To achieve this goal, the present study deals with the three-dimensional simulation of the two-phase flow field from the Eulerian point of view. OpenFOAM has been used to solve the equations of conservation...
Study of Surface Evaporation Currents Due to Wind-Induced in Aquatic Canopy Areaswith Floating Vegetation
, M.Sc. Thesis Sharif University of Technology ; Jamali, Mirmosaddegh (Supervisor)
Abstract
The aquatic canopy areas such as wetlands play an important role in ecology of these area. The exchange flow between open water and vegetated area occurs due to sunlight and surface cooling. Wind also causes surface evaporation and create a cold layer at the surface of water. The creation of exchange flow and its magnitude depends on parameters like solid volume fraction and thermal gradient. In this thesis, the goal is to determine the effects of floating vegetation on the hydrodynamic characteristics of exchange flowas a result of surface cooling experimentally. In this research, the PIV method was used to measure velocity profiles. In the experiments, solid volume fraction, depth of...
Geometric Modelling of Naturally Fractured Reservoirs Using Aerial Image Processing and Two-Phase Flow Simulation
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor)
Abstract
It has been demonstrated that the key features of fracture networks can be identified with the help of high-resolution aerial images of outcrops (rock formations exposed at the Earth's surface) obtained by drones and photogrammetry. The aim of this study is to utilize these images to improve the geometrical modeling of Naturally Fractured Reservoirs (NFRs). Initially, an algorithm is developed for processing aerial images of outcrops, so that the pattern of fracture network can be obtained. After obtaining the fracture network, the Embedded Discrete Fracture Model (EDFM) implemented in the MATLAB Reservoir Simulation Toolbox (MRST) is employed to study two-phase (oil-water) flows in the...
Synthesis of Cs-Based Mixed Cation Hybrid Lead Halide Perovskites for Solar Cell Application
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Mohammad Reza (Supervisor) ; Abachi, Parvin (Supervisor)
Abstract
With high power conversion efficiency, comparable to silicon solar cells, the conventional perovskite solar cells (PSCs) are leading the photovoltaic research scene. However, they have poor stability in operation due to instability of organic-inorganic hybrid PSCs. Several methods have been proposed to improve their stability including Substitution of the organic component by an inorganic one For example, inorganic perovskite compound such as 〖 CsPbI〗_3 with bandgap about 1.7 eV is a good candidate. However, it requires high synthesis temperature (about 300 ℃), and the resulting cell has a lower efficiency than the organic one. Introduction of Cs, as an inorganic element, into organic...
Low-cost air-stable perovskite solar cells by incorporating inorganic materials
, Article New Journal of Chemistry ; Volume 45, Issue 2 , 2021 , Pages 788-795 ; 11440546 (ISSN) ; Mohammadi, M. R ; Abachi, P ; Martinez Chapa, S. O ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
Herein, we demonstrate a new fabrication strategy for low-cost and stable-operation perovskite solar cells (PSCs) suitable for commercialization. This is performed by fabrication of the device under ambient conditions using a Cs0.05(MA0.17FA0.83)0.95Pb(Br0.17I0.83)3 formulation as the mixed cation and halide (MCH) perovskite and CuInS2 (CIS) as the inorganic hole transporting layer. The deposited MCH perovskite with uniform, compact and smooth microstructure containing equiaxed large grains showed excellent thermal and structural stability under intense conditions at 85 °C for 2 h in humid air (i.e., 45% relative humidity). Moreover, it had higher phosphorescence emission, absorption and...
Adversarial Attack to Deep Learning Networks via Imperceptible Sparse Perturbation
, M.Sc. Thesis Sharif University of Technology ; Ghaemmaghami, Shahrokh (Supervisor) ; Marvasti, Farokh (Supervisor) ; Amini, Sajad (Co-Supervisor)
Abstract
Nowadays, methods based on deep learning networks are the most effective artificial in telligence methods. Although they have achieved success in various fields (such as machine vision and object recognition), practical and experimental cases show the fragility of deep learning networks against perturbations and unwanted changes of the input pattern. All these perturbations must be in a way that the main class of the perturbed input pattern can be rec ognized by human, but the network makes a mistake in recognizing its correct class. This thesis seeks a more accurate evaluation by designing adversarial attacks such that the main class of the adversarial pattern is detectable by human...
Recent activities in science and technology and the progress of women in physics in the last three years in Iran
, Article AIP Conference Proceedings, Stellenbosch ; Volume 1517 , 2013 , Pages 108-109 ; 0094243X (ISSN); 9780735411388 (ISBN) ; Azad, M. T ; Mahmoudi, N ; Izadipanah, N ; Eshghi, N ; Sharif University of Technology
2013
Abstract
For the 4th IUPAP International Conference of Women in Physics, we report on activities in science and engineering in Iran, and conditions for women in physics, in the three years since the 3rd IUPAP International Conference of Women in Physics was held in 2008. Iran has made prominent advancements and astonishing progress in laser technology, biotechnology, nanotechnology, genetics, computer software and hardware, and robotics. Iranian scientists have been very productive in several experimental fields, such as pharmaceutical, organic, and polymer chemistry. Conditions for women in physics have improved greatly in recent years. A project to improve the environment for learning physics, and...
Ab initio study of electronic effects in the ZnO/TiO2 core/shell interface: Application in dye sensitized solar cells
, Article RSC Advances ; Vol. 4, issue. 1 , April , 2014 , p. 301-307 ; Nafari, N ; Taghavinia, N ; Sharif University of Technology
2014
Abstract
Core/shell structure of ZnO nanowires coated with a monolayer of TiO 2 is investigated using Density Functional Theory (DFT). The electronic states of the semiconductor is calculated and compared before and after coating of the TiO2 monolayer on a ZnO [101 0] surface. The effect of TiO2 coating induce surface states changes and shifts the conduction and valence band edges to higher energies. Our results, in qualitative agreement with the experimental work of Matt Law et al. (J. Phys. Chem. B, 110, 22652), show an increase in open circuit voltage and a decrease in short circuit current in ZnO/TiO2 core shell dye sensitized solar cells. Regarding the semiconductor density of states (DOS), TiO2...
Analyzing factors effective on the development of relationship commitment
, Article Proceedings of the 2012 International Conference on Artificial Intelligence, ICAI 2012, 16 July 2012 through 19 July 2012 ; Volume 1 , July , 2012 , Pages 398-404 ; 1601322186 (ISBN) ; 9781601322180 (ISBN) ; Lotfi, N ; Karami, N ; Sharif University of Technology
2012
Abstract
Due to the important role of commitment and trust in the relationship marketing, the factors which can directly result in a committed relationship along with the factors which can influence the commitment through influencing trust, according to the model of commitment and trust by (Morgan & Hunt, 1994) have been introduced and their level of importance has been investigated here. The article uses fuzzy cognitive maps (FCMs) in the proposed model to find the most important paths leading to relationship commitment. The FCM analyzes the responses of a group of 30 people including general practitioners in dentistry, managers of dental departments in some of the public clinics and hospitals who...
Morphological dependence of light backscattering from metallic back reflector films: Application in dye-sensitized solar cells
, Article Physica Status Solidi (A) Applications and Materials Science ; Volume 212, Issue 4 , January , 2015 , Pages 785-790 ; 18626300 (ISSN) ; Ghazyani, N ; Taghavinia, N ; Sharif University of Technology
Wiley-VCH Verlag
2015
Abstract
Conventionally, a film of TiO2 particles of 300 nm size is employed in Dye-sensitized solar cells (DSCs) as the back reflector film to enhance the light harvesting. Perfect reflectance of silver in visible and near infrared motivates to investigate its potential as the material for the light back reflector film in DSCs. In this study, light back reflector films consisting of 300 nm-sized silver particles, as well as vacuum evaporated silver flat film, were fabricated and compared to 300 nm-sized rutile-type TiO2 particulate reflector film to study their optical aspects. Conventional TiO2 rutile-type particulate film demonstrates slightly lower performance...
Monolithic dye sensitized solar cell with metal foil counter electrode
, Article Organic Electronics ; Volume 57 , June , 2018 , Pages 194-200 ; 15661199 (ISSN) ; Taghavinia, N ; Ghazyani, N ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Monolithic dye-sensitized solar cells are conventionally fabricated using carbon composite layer as the counter electrode. In the current research, the brittle carbon composite layer is replaced with a metal foil, aiming to decrease the device series resistance and using less catalyst material in counter electrode. This metallic structure has also an advantage of mechanical strength and decreases the fabrication complexity. The counter electrode is prepared by electrodepositing Cr film followed by electrodepositing Pt nanoparticles on a metal foil. As the porous spacer layer, different composite layers of SiO2, TiO2, and Al2O3 are investigated and the best results are obtained for TiO2...
A compact versatile microbial fuel cell from paper
, Article ASME 2013 11th Int. Conf. on Fuel Cell Science, Eng. and Technology Collocated with the ASME 2013 Heat Transfer Summer Conf. and the ASME 2013 7th Int. Conf. on Energy Sustainability, FUELCELL 2013 ; 2013 ; 9780791855522 (ISBN) ; Hashemi, N ; Hashemi, N ; Sharif University of Technology
2013
Abstract
Microbial fuel cells (MFCs) have been a potential green energy source for a long time but one of the problems is that either the technology must be used on a large scale or special equipment have been necessary to keep the fuel cells running such as syringe pumps. Paper-based microbial fuel cells do not need to have a syringe pump to run and can run entirely by themselves when placed in contact with the fluids that are necessary for it to run. Paper-based microbial fuel cells are also more compact than traditional MFCs since the device doesn't need any external equipment to run. The goal of this paper is to develop a microbial fuel cell that does not require a syringe pump to function. This...
Decentralized model predictive voltage control of islanded DC microgrids
, Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 ; Mahdian Dehkordi, N ; Sadati, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This paper proposes a novel decentralized control approach for islanded direct-current (DC) microgrids (MGs) based on model predictive control (MPC) to regulate the distributed generation unit (DGU) output voltages, i.e. the voltages of the point of common coupling (PCC). A local controller is designed for each DGU, in the presence of uncertainties, disturbances, and unmodeled dynamics. First, a discrete-time state-space model of an MG is derived. Afterward, an MPC algorithm is designed to perform the PCC voltage control. The proposed MPC scheme ensures that the PCC voltages remain within an acceptable range. Several simulation studies have been conducted to illustrate the effectiveness of...
Intelligent optimal feed-back torque control of a 6DOF surgical rotary robot
, Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 ; Ebrahimi Toulkani, N ; Zhilakzadeh, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Sophisticated surgeons are widely indicating the use of surgical robots in order to reject human error, increase precision, and speed. Among well-known robotic mechanisms, parallel robots are broadly more investigated regarding their special characters as higher acceleration, speed, and accuracy, and less weight. Specific surgical procedures confine, and restrict their workspace, while controlling and validating the robots are complicated regarding to their complex dynamic. To this end, in this paper, a 6-DOF robot, with rotary manipulators, is designed and controlled. Addressing nonlinearity of parallel robots, an innovative methodology is formulated to robustly penalize the error of...
Semi-Real evaluation, and adaptive control of a 6DOF surgical robot
, Article 11th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2020, 4 February 2020 through 6 February 2020 ; 2020 ; Ebrahimi Toulkani, N ; Zhilakzadeh, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Sophisticated surgeons are widely indicating the use of surgical robots in order to reject human error, increase precision, and speed. Among well-known robotic mechanisms, parallel robots are broadly more investigated regarding their special characters as higher acceleration, speed, and accuracy, and less weight. Specific surgical procedures confine and restrict their workspace, while controlling and validating the robots are complicated based on their complex dynamic. To this end, in this paper, a 6-DOF robot, with linear manipulators, is designed and controlled. Addressing the inherent nonlinearity of the robot mechanism, an adaptive PID manipulator is employed and validated with nonlinear...
Modeling superconductive fault current limiter using constructive neural networks
, Article 2007 IEEE International Symposium on Industrial Electronics, ISIE 2007, Caixanova - Vigo, 4 June 2007 through 7 June 2007 ; 2007 , Pages 2859-2863 ; 1424407559 (ISBN); 9781424407552 (ISBN) ; Sadati, N ; Hosseini, M. N ; Sharif University of Technology
2007
Abstract
Although so many advances have been proposed in the field of artificial intelligence and superconductivity, there are few reports on their combination. On the other hand, because of the nonlinear and multivariable characteristics of the superconductive elements and capabilities of neural networks in this field, it seems useful to apply the neural networks to model and control the superconductive phenomena or devices. In this paper, a new constructive neural network (CNN) trained by two different optimization algorithms; back-propagation and genetic algorithm, is proposed which models the behavior of the superconductive fault current limiters (SFCLs). Simulation results show that the proposed...
Satellite attitude tracking using optimal neuro-controller
, Article 2003 IEEE Aerospace Conference, Big Sky, MT, 8 March 2003 through 15 March 2003 ; Volume 6 , 2003 , Pages 2663-2669 ; 1095323X (ISSN); 078037651X (ISBN); 9780780376519 (ISBN) ; Sadati, N ; Tehrani, N. D ; Sharif University of Technology
2003
Abstract
In this paper, a new control strategy for optimal attitude tracking control of a multivariable satellite system has been presented. The approach is based on a Multilayer Perceptron Neural Network (MLPNN) and a classical PD Controller for its initial stabilization. It is shown how the network can be employed as a multivariable self-organizing and self-learning controller in conjunction with a PD controller for attitude control of a satellite. By using three thrusters and quaternion for kinematics representation, the attitude dynamics of the satellite has been presented. In contrast to the previous classical approaches, it is shown how this controller can be carried out in an on-line manner...
Effect of heat treatment cycle on the mechanical properties of machinable austempered ductile iron
, Article 16th International Metallurgical and Materials Conference, METAL 2007, 22 May 2007 through 24 May 2007 ; 2007 ; Baghersaee, N ; Varahram, N ; Hanumantha Rao, M ; Rao, G. V.S. N ; Sharif University of Technology
TANGER spol. s r.o
2007
Abstract
ADI have been used for a wide variety of application in automotive,rail,and heavy engineering industry because of its excellent mechanical properties such as high strength with good ductility,good wear resistance,and good fatigue properties. The properties of austempered ductile iron are dependent on both chemistry and heat treatment, which has lead to invention of MADI (machinable austempered ductile iron). MADI is a new class of ductile iron with superior mechanical property than regular ductile iron with the same machinability characteristic. In this study Different cycles of austempering process (austenitization and austempering cycle) applied Due to the effect of heat treatment cycle on...
Effect of heat treatment cycle on the mechanical properties of machinable austempered ductile iron
, Article 24th ASM International Heat Treating Conference and Exposition, Detroit, MI, 17 September 2007 through 19 September 2007 ; 2007 , Pages 323-327 ; 9781604239300 (ISBN) ; Baghersaee, E. N ; Varahram, N ; Rao, M. H ; Rao, G. V. S. N ; Sharif University of Technology
2007
Abstract
ADI have been used for a wide variety of applications in automotive, rail, and heavy engineering industry because of its excellent mechanical properties such as high strength with good ductility, good wear resistance, and good fatigue properties. The properties of austempered ductile iron are dependent on both chemistry and heat treatment, which has lead to invention of MADI (machinable austempered ductile iron). MADI is a new class of ductile iron with superior mechanical property than regular ductile iron with the same machinability characteristic. In this study Different cycle of austempering process (austenitization and austempering cycle) applied Due to the effect of heat treatment...